PSLE Winnie baked a total of 48 large and small cakes in the ratio of 7 : 5. She decorated each cake with some raspberries in the ratio of 9 : 4. She used a total of 322 raspberries to decorate all the small cakes and 9 large cakes.
- How many small cakes did Winnie bake?
- What was the number of raspberries used to decorate all the small cakes?
- How many more raspberries did Winnie need to decorate the remaining large cakes?
(a)
Fraction of the cakes that were large ones =
77 + 5 =
712Number of large cakes
=
712 x 48
= 28
Number of small cakes
= 48 - 28
= 20
|
Large cakes |
Small cakes |
Total |
Number |
9 |
20 |
|
Value |
9 u |
4 u |
|
Total value |
81 u |
80 u |
161 u |
(b)
Number of raspberries used to decorate 9 large cakes and 20 small cakes
= 81 u + 80 u
= 161 u
161 u = 322
1 u = 322 ÷ 161 = 2
Number of raspberries used to decorate all the small cakes
= 80 u
= 80 x 2
= 160
(c)
Number of raspberries to decorate one large cake
= 9 u
= 9 x 2
= 18
Number of remaining large cakes that were decorated yet
= 28 - 9
= 19
Number of more raspberries that Winnie needed to decorate the remaining large cakes
= 19 x 18
= 342
Answer(s): (a) 20; (b) 160; (c) 342